JavaScript Working with Arrays

Lesson Details:

I: Introduction

A: Learn javascript course

I: Introduction

A: Learn javascript course

I: Introduction

A: Learn javascript course

I: Introduction

A: Learn javascript course

Now you have an outline, you can start writing. It is always better to write something even if it’s not great. You can always edit it later. Now the hard part, you need to write about Javascript working with arrays. Try something like this out, but feel free to write your own, it’s your article after all.

Javascript working with arrays

The goal of this section is to learn how to use JavaScript arrays to create a web page that allows the user to make a choice using checkboxes and then display the result on another web page. If you are unfamiliar with JavaScript programming or have not taken the Learn JavaScript course, this section will introduce you to JavaScript programming and show you how to work with arrays in JavaScript. If you have already taken the Learn JavaScript course, you can just review these topics here. It is recommended that you take the JavaScript programming exam found on the Exercises page. This will help you to solidify your understanding of arrays in JavaScript.

JavaScript works with arrays similar to how the language works with objects. An array is a collection of similar elements called members. The elements are typically numbers or strings, but there are other types of elements as well. Each member has a name and an associated value, also called an index. An array is like an address book. Each entry, or element, has a name and a value. The names are used for accessing the values of the elements. Values can be either one or multiple items at once, like a single name or multiple names that represent an address book entry. Many languages also use zero based indexing, which means that the first element in an array is indexed at zero (or you don’t specify an index at all). For example, if you had an array named “Customers”, you could access elements at index zero (the first element) through two (the third element) by writing Customers[0], Customers[1], and Customers[2]. This would be the same as writing Customer[0], Customer[1], and Customer[2] in some languages.

Arrays are created using square brackets ([]) containing the name of the array followed by zero or more comma separated values between square brackets followed by another set of square brackets containing the name of the array again followed by zero or more commas followed by another set of square brackets containing the type of array followed by zero or more commas followed by another set of square brackets containing the name of the array again followed by zero or more commas followed by another set of square brackets containing the number of dimensions in the array followed by zero or more commas followed by another set of square brackets containing the name of the array followed by zero or more commas followed by another set of square brackets containing the length of each dimension in the array followed by zero or more commas followed by another set of square brackets containing the name of the array again followed by zero or more commas followed by another set of square brackets containing an initial value for each member in each dimension of the array separated by spaces. We want our arrays to be multidimensional, so we will specify three dimensions with index values starting at 0 for each dimension. Our initial values will just be zeros for now because we will fill them later. So to create our first array named “Customers”, we will write:

var Customers = [ [ ], [ ], [ 0 ] ]; 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 // // Javascript working with arrays // function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } function main () { return ; } var Customers = [ [ ] , [ ] , [ 0 ] ] ; var arr = new Array ( ) ; var arr = new Array ( ) ; var arr = new Array ( ) ; var arr = new Array ( ) ; var arr = new Array ( ) ; var arr = new Array ( ) ; var arr = new Array ( ) ; var arr = new Array ( ) ; var arr = new Array ( )